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词条 Alpha Ceti
释义

  1. Nomenclature

  2. Structure

  3. Namesakes

  4. See also

  5. References

  6. External links

{{about|Menkar, one of the brightest stars in Cetus|the Star Trek "Ceti Alpha" locations|List of Star Trek planets (C–F)}}{{Starbox begin
| name = α Ceti
}}{{Starbox image
| image={{Location mark
|image=Cetus constellation map.svg|alt=|float=center|width=280
|label=|position=right
|mark=Red circle.svg|mark_width=12|mark_link=α Ceti
|x=124|y=200
}}
|caption=Location of α Ceti (circled)
}}{{Starbox observe
| epoch = J2000
| constell = Cetus
| ra = {{RA|03|02|16.77307}}[1]
| dec = {{DEC|+04|05|23.0596}}[1]
| appmag_v = 2.53[3]
}}{{Starbox character
| class = M1.5 IIIa[4]
| b-v = +1.64[3]
| u-b = +1.93[3]
| variable = None[7]
}}{{Starbox astrometry
| radial_v = {{nowrap|–26.08 ± 0.02}}[8]
| prop_mo_ra = {{nowrap|-10.41 ± 0.51}}[1]
| prop_mo_dec = {{nowrap|-76.85 ± 0.36}}[1]
| parallax = 13.09
| p_error = 0.44
| parallax_footnote = [1]
| absmag_v = {{nowrap|–3.2 ± 0.3}}[4]
}}{{Starbox detail
| mass = {{nowrap|2.3 ± 0.2}}[13]
| radius = {{nowrap|89 ± 5}}[13]
| luminosity = {{nowrap|1455 ± 328}}[13]
| temperature = {{nowrap|3,795 ± 70}}[13]
| metal_fe = {{nowrap|0.00 ± 0.30}}[13]
| gravity = 0.9 ± 0.1[13]
| rotational_velocity = 6.9[19]
| age =
}}{{Starbox catalog
| names = Menkar, Menkab, Mekab, Monkar, Al Minhar, 92 Ceti, HR 911, BD+03° 419, HD 18884, SAO 110920, FK5 107, HIP 14135.
}}{{Starbox reference
| Simbad = Menkar
}}{{Starbox end}}

Alpha Ceti (α Ceti, abbreviated Alpha Cet, α Cet), also named Menkar,[1] is the second-brightest star in the constellation of Cetus. It is a cool luminous red giant about 250 light years away.

Nomenclature

Alpha Ceti is the star's Bayer designation. It has the traditional names Menkar or Menkab, the former deriving from the Arabic word منخر manħar "nostril" (of Cetus). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[2] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[3] included a table of the first two batches of names approved by the WGSN; which included Menkar for this star.

This star, along with γ Cet (Kaffaljidhma), δ Cet, λ Cet (also Menkar), μ Cet, ξ1 Cet and ξ2 Cet were Al Kaff al Jidhmah, "the Part of a Hand".[4]

In Chinese, {{lang|zh|天囷}} ({{lang|zh-Latn|Tiān Qūn}}), meaning Circular Celestial Granary, refers to an asterism consisting of α Ceti, κ1 Ceti, λ Ceti, μ Ceti, ξ1 Ceti, ξ2 Ceti, ν Ceti, γ Ceti, δ Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, α Ceti itself is known as {{lang|zh|天囷一}} ({{lang|zh-Latn|Tiān Qūn yī}}, {{lang-en|the First Star of Circular Celestial Granary}}.)[5]

Structure

Despite having the Bayer designation α Ceti, at visual magnitude 2.54 this star is actually not the brightest star in the constellation Cetus. That honor goes instead to Beta Ceti at magnitude 2.04. Menkar is a red giant with a stellar classification of M1.5 IIIa. It has more than twice the mass of the Sun and, as a giant star has expanded to about 89 times the Sun's radius. The large area of the photosphere means that it is emitting about 1,455 times as much energy as the Sun, even though the effective temperature is only 3,795 K (compared to 5,778 K on the Sun). The relatively low temperature gives Menkar the red hue of an M-type star.[25]

Menkar has evolved from the main sequence after exhausting the hydrogen at its core. It has also exhausted its core helium, becoming an asymptotic giant branch star, and will probably become a highly unstable star like Mira before finally shedding its outer layers and forming a planetary nebula, leaving a relatively large white dwarf remnant.[27] It has been observed to vary in brightness, but only with an amplitude of about one hundredth of a magnitude.[28]

Namesakes

Menkar (AK-123) was a United States Navy Crater class cargo ship named after the star.

See also

  • Alpha Ceti in fiction

References

1. ^{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt | title=IAU Catalog of Star Names |accessdate=28 July 2016}}
2. ^{{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|accessdate=22 May 2016}}
3. ^{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/WGSN_bulletin1.pdf | title=Bulletin of the IAU Working Group on Star Names, No. 1 |accessdate=28 July 2016}}
4. ^Star Name - R.H. Allen p.160
5. ^{{zh icon}} AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日
6. ^1 {{cite journal|bibcode=2002MNRAS.331...45K|title=New periodic variables from the Hipparcos epoch photometry|journal=Monthly Notices of the Royal Astronomical Society|volume=331|issue=1|pages=45|last1=Koen|first1=Chris|last2=Eyer|first2=Laurent|year=2002}}
7. ^1 2 3 4 5 {{cite journal | first=F. | last=van Leeuwen |date=November 2007 | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 |arxiv = 0708.1752 }}
8. ^1 {{cite journal | display-authors=1 | last1=Famaey | first1=B. | last2=Jorissen | first2=A. | last3=Luri | first3=X. | last4=Mayor | first4=M. | last5=Udry | first5=S. | last6=Dejonghe | first6=H. | last7=Turon | first7=C. | title=Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters | journal=Astronomy and Astrophysics | volume=430 | issue=1 | pages=165–186 |date=January 2005 | doi=10.1051/0004-6361:20041272 | bibcode=2005A&A...430..165F |arxiv = astro-ph/0409579 }}
9. ^1 {{citation | display-authors=1 | last1=Massarotti | first1=Alessandro | last2=Latham | first2=David W. | last3=Stefanik | first3=Robert P. | last4=Fogel | first4=Jeffrey | title=Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity | journal=The Astronomical Journal | volume=135 | issue=1 | pages=209–231 |date=January 2008 | doi=10.1088/0004-6256/135/1/209 | bibcode=2008AJ....135..209M }}
10. ^1 2 3 {{cite journal | display-authors=1 | last1=Johnson | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | pages=99 | year=1966 | bibcode=1966CoLPL...4...99J }}
11. ^1 2 {{citation | last1=Tsuji | first1=T. | title=Cool luminous stars: the hybrid nature of their infrared spectra | journal=Astronomy and Astrophysics | volume=489 | issue=3 | pages=1271–1289 |date=October 2008 | doi=10.1051/0004-6361:200809869 | bibcode=2008A&A...489.1271T |arxiv = 0807.4387 }}
12. ^1 2 3 4 5 6 {{citation | display-authors=1 | last1=Wittkowski | first1=M. | last2=Aufdenberg | first2=J. P. | last3=Driebe | first3=T. | last4=Roccatagliata | first4=V. | last5=Szeifert | first5=T. | last6=Wolff | first6=B. | title=Tests of stellar model atmospheres by optical interferometry. IV. VINCI interferometry and UVES spectroscopy of Menkar | journal=Astronomy and Astrophysics | volume=460 | issue=3 | pages=855–864 |date=December 2006 | doi=10.1051/0004-6361:20066032 | bibcode=2006A&A...460..855W |arxiv = astro-ph/0610150 }}
13. ^1 {{cite conference | display-authors=1 | last1=Wittkowski | first1=M.| last2=Boboltz | first2=D. A. | last3=Driebe | first3=T. | last4=Ohnaka | first4=K. | contribution=Polychromatic Interferometry of Mira Variables | title=Why Galaxies Care About AGB Stars: Their Importance as Actors and Probes, proceedings of the conference held 7-11 August 2006 at University Campus, Vienna, Austria | journal=Why Galaxies Care About Agb Stars: Their Importance as Actors and Probes | series=ASP Conference Series | volume=378 | editor1-first=F. | editor1-last=Kerschbaum | editor2-first=C. | editor2-last=Charbonnel | editor3-first=R. F. | editor3-last=Wing | page=262 |date=November 2007 | bibcode=2007ASPC..378..262W }}
14. ^1 {{citation | first1=James B. | last1=Kaler | work=Stars | publisher=University of Illinois | title=MENKAR (Alpha Ceti) | url=http://stars.astro.illinois.edu/sow/menkar.html | accessdate=2011-12-24 }}
15. ^1 {{citation|title=The Colour of Stars |date=December 21, 2004 |work=Australia Telescope, Outreach and Education |publisher=Commonwealth Scientific and Industrial Research Organisation |url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |accessdate=2012-01-16 |deadurl=yes |archiveurl=https://www.webcitation.org/6630AbtJZ?url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |archivedate=March 10, 2012 }}
[6][7][8][9][10][11][12][13][14][15]
}}

External links

  • Assorted figures related to Alpha Ceti
{{Stars of Cetus}}

9 : Bayer objects|Cetus (constellation)|M-type giants|Stars with proper names|Henry Draper Catalogue objects|Flamsteed objects|Hipparcos objects|HR objects|Durchmusterung objects
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